For those that don't know, I'm a fixed operations (parts and service) consultant for car dealerships. Been doing it since 1981. Our industry works pretty good most of the time, but we are loosey goosey, and sometime work with gentlemens agreements. Read this whole link, but at least from page 5 on http://www.bar.ca.gov/80_BARResources/07_AutoRepair/Auto_Rep_Guide.pdf This is Hal's Cliffnotes California BAR requires a written estimate on service work. Any change needs an approval in person or by phone. The vendor is required to put the time, date, and the revised amount. The price can’t be changed from a complete original estimate for any reason, including tax, if it included tax. So a vender has to state if the estimate includes tax or not. Can’t be even a penny over the estimate, the rumor of 10% over is OK, is false. The supplemental increase for more parts or labor is the only reason for a revised estimate. Never sign a blank repair order. I, myself would require an email stating the changes in price for additional parts and labor, not a change in the original estimate. If I was a vendor, I would want my customer to approve the increase in cost for parts and or labor. We have email now. Send the customer an email laying out the increase in cost, have him respond to the email authorizing the increase from the estimate. So, if you take your car to a shop in CA. Three things need to happen. The vendor is required to open a repair order for the job. You must sign it, authorize the repair, and be given a copy of the repair order. If the estimate can't be given at that time, it should be noted that the estimate will follow. If there is an estimate fee for tear down, and the customer declines, he will have to pay the tear down fee he authorized. The tear down fee must include the labor to put it back together in case you decline to work. Most states have similar laws to protect customers and vendors similar to California. These laws are there to protect both vendors/dealers and their customers.